The Genesis of Steel

Steel, an alloy of iron and carbon, is produced in a two-stage process. First, the raw material—is smelted, producing molten iron. In the second stage, iron is converted into steel by removing impurities such as sulfur, phosphorus and excess carbon and adding alloying elements such as manganese, nickel, chromium and vanadium. The molten steel is then continuously cast, and cut to the prescribed length. These castings are then rolled to make a variety of steel products.

The Genesis of Steel

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Strength Vs. Ductility

Steel is a metal with great tensile strength and ductility. It can extend these qualities to concrete. In other words, it reinforces concrete. Steel in the form of bars has been doing this job for more than a century now. Naturally, the quality of steel has an important role in deciding the quality of concrete. Research has periodically produced various kinds of steel bars with qualities that make concrete more stable. It started with mild steel (MS); TOR steel and various grades of TMT followed.

Strength Vs. Ductility

Indian standards specify that the MS bars have a tensile strength of 250MPa. TOR steel is required to have 415MPa. This increase in strength enhances the factor of safety in construction by a huge margin. Even today, many buildings are designed assuming a strength of 250MPa for Fe 415, a higher grade steel. Hence buildings built with Fe 415 grade steel provide a factor of safety that is much higher than that is required. But the higher strength of Fe 415 grade TOR steel rebars brings down ductility, or the ability to retain shape even under pressure, which is also a major requirement of steel reinforcement

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Steel that survives earthquakes

Ductility of steel bars provide earthquake resistance

Concrete which is just made up of cement, sand and water is likely to break when it is stretched or twisted even by a small degree. This is because it has very low tensile strength. But when steel bars of optimum ductility goes into this concrete, they indirectly attain a tensile strength. “Buildings built with optimum ductilitay steel bars would be able to withstand mild tremors and earthquakes. ” says Reji Zachariah a Structural Engineer. He also adds that such building may shake or tremble a bit, but would never collapse when earthquakes of small-medium scale strikes. Such building would have the necessary ‘flexibility’ and would easily recover to their former state. This is because they have ductile TMT steel in their structure. On the other hand, buildings built with ordinary steel bars can only be left to their fate.

Steel that survives earthquakes

Experienced architects say that some regions of Kerala are prone to seismic attacks. In such areas, a ‘framed’ construction style can be adopted. The concrete pillars, beams and ceiling are first constructed and the walls are built in between the pillars. This would endow a flexible yet binding strength to the overall structure

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TMT Steel – Inner strength of buildings and houses.

Most people are particular about what cement or what paint to use when building a house, but don’t pay much attention to the brand quality of the steel bars, which really play a critical role in the strength and durability of the building.

Strength Vs. Ductility (2)

The general outlook of Malayalees when building their house is that it should last for generations. Little wonder, they never compromise on its quality. They have a clear idea on what cement to be used or what paint they should apply on the interiors and the exteriors. On the other hand, when asked what steel bars would be used for the structure, the average homemaker is clueless about it. He would be uncertain about it and may say “ a steel bar of quality”

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